Hello I would like to paint or coat my rusty exhaust manifolds . Has anyone tried some of the stuff in spray cans available at the parts store thanks in advance 

I like the VHT brand of high temperature paints. They sell a high temperature primer and then several top coat colors to choose from. In my personal opinion, I like to media blast rusty exhaust manifolds prior to painting. The media blasting provides a good texture to the iron for good paint adhesion. The fact that I have my own media blast cabinet helps!

  Ron Lane,  Meridian, ID

You can use chemicals like Naval Jelly to remove rust.  It's messy.  I have them bead blasted then paint them with Eastwood's High Temp Coating.  It has the look of cast iron. A little goes a long way.  As you can see, I have had this can for years.  It's nice because you can touch them up later.